A thermal reader/writer utilizes the interaction of mixed leuco dye and developer for repetitive writing and erasing. A reversible developer is used to achieve a rewritable property for development and disappearance in color under control of heated temperature and cooling time. By way of example, when a thermofusible ink containing a mixture of leuco dye and developer is heated over their melting point (for example at a temperature of about 170 degrees centigrade), dye and developer become soluble in one another in a printed layer, and when the ink is rapidly cooled in the soluble condition, dye and developer undergo crystallization under their mixed condition to maintain the coloring state. On the contrary, when the ink over the melting point is gradually cooled, dye and developer individually come to crystallization into an achromatized state without retaining the coloring state. However, even when the ink is heated during a given time at a temperature (around 120 to 140 degrees centigrade) less than the melting point, dye and developer may be separately crystallized into an achromatized state. In this way, an operator can select writing or erasing of thermal reader/writer by controlling the crystallizing process in the mixture of dye and developer. A thermal head is used for writing, and there are many methods for erasing.
Patent Document 1 below listed discloses a printing device which comprises storing means for accommodating a stack of media in a predetermined insertion direction for a printer, conveyor means for transporting the media to the printer, discrimination means for discriminating the back, forth, right or left direction of the inserted media relative to the printer, and print control means for controlling the printer to print on the media information depending on the discriminated result of the discrimination means.
Patent Document 2 teaches a coinless slot machine system provided with a printer for issuing tickets for a slot machine. Specifically, this coinless slot machine system can issue coupons to omit paying out of coins in order to drastically reduce safekeeping money for casino operation as is widely prevalent. However, utilization of coupons made of paper requires issuance of new tickets each time gaming machines for play are exchanged or on a liquidation basis, and therefore, it demands a vast number of tickets and this poses an impediment of cost-cutting.
[Patent Document 1] Japanese Patent No. 2,796,021
[Patent Document 2] U.S. Pat. No. 6,048,269